This is not very useful as alert, it doesn't say what service is failing. I can't find it in karma, so I guess it was a temporary alert that got resolved itself.
I created an issue on TPA side to improve those alerts: https://gitlab.torproject.org/tpo/tpa/team/-/issues/41928
Quoting alertmanager--- via anti-censorship-alerts (2024-12-10 09:13:11)
Total firing alerts: 1 Total resolved alerts: 0
## Firing Alerts
Time: 2024-12-10 08:12:40.651 +0000 UTC Summary: Website is too slow. Description: Website has been too slow to respond in the last hour, not achieving our availbility target (95%) in response times (1s), instead having a 1.134s response time.
##Resolved Alerts